1. Field of the Invention
The present invention relates to sleepwalking, and in particular to a system and method for detecting possible sleepwalking episodes and providing one or more alerts and/or mitigating one or more control actions when a possible sleepwalking episode has been detected.
2. Description of the Related Art
Sleepwalking (also called noctambulism or somnambulism) is a sleep disorder in which an individual engages in activities while asleep or in a sleeplike state that are normally associated with wakefulness. Such activities may include, for example, walking, dressing, eating, or even driving a car. Sleepwalking is most prevalent in pre-adolescent individuals, although it can affect people of any age. Because a sleepwalker typically remains in a deep (unconscious) sleep state throughout the episode, he or she may be difficult to awaken and will probably not remember the sleepwalking incident. Thus, while sleepwalking itself does not inherently pose a serious health concern to those who experience it, the absence of full arousal and full awareness during sleepwalking episodes does present a significant risk of injury to the individual or others as a result of accidents that may occur. For obvious reasons, this risk of injury is of great concern to parents of child sleepwalkers and to other caregivers in general.
U.S. Pat. No. 5,963,137 describes a system for monitoring the movement of an individual, such as a sleepwalker, that provides an alarm signal when a sleep-time excursion form bed is detected. The system employs a magnetic switch that is coupled to an audible and visual alarm system and a connecting strap that is fitted on one end to the individual being monitored by a standard clothing suspender fastener and on the other end to the magnetic switch by way of a hook assembly. The magnetic switch houses a solid magnetic cylinder which, when separated from the other half of the switch as a result of the forward or side displacement of the individual, and thus the strap and hook assembly, opens the circuit and activates the alarm system.
While the system described in U.S. Pat. No. 5,963,137 provides a solution for monitoring the movement of an individual, such as a sleepwalker, that may be effective under certain conditions, it requires that the individual being monitored be physically tethered to the alarm activating mechanism. Such physical tethering is uncomfortable as it greatly restricts the freedom of movement during sleep, possibly to the extent of adversely affecting that individual's sleep. In addition, the system described in U.S. Pat. No. 5,963,137 only guards against a simple type of movement, i.e., a simple displacement of the individual being monitored that would cause the tethering mechanism to become disconnected. It does not measure more meaningful and precise movement information (other then a simple displacement) to give a caregiver options to better define permitted and prohibited movements. Thus, there is a need for a system that is able to detect sleepwalking episodes without greatly restricting the freedom of movement of that individual being monitored that also measures more meaningful and precise movement information of the individual being monitored.